Astronomers are getting an idea of what they might see early on the Fourth of July when a NASA probe slams into a comet.
A photo taken by the Hubble Space Telescope shows a 1,400-mile plume of dust spewing from the comet toward the sun.
Johns Hopkins University astronomy professor Paul Feldman says light from the sun most likely heated a pocket of volatile gas trapped beneath the surface of the comet, triggering an eruption.
Researchers hope the collision Monday provides their first look into the heart of the comet, perhaps offering clues about the formation of the solar system.
It'll have the force of four-and-a-half tons of TNT, creating a fireworks flash that may be visible to the naked eye in parts of the Western Hemisphere. In the U.S., it might be visible anywhere west of a line from Chicago to Atlanta.